Spherical shaped pore structured cermet supports for solid oxide fuel cells

Anode-supported solid oxide fuel cells (SOFC) have been extensively investigated due to their ease of fabrication, robustness, and high electrochemical performance. In this study, anode supported SOFCs are fabricated and characterized as a function of the components in the anode supports. The addition of Fe2O3 to NiO–yttria stabilized zirconia (YSZ) anode support tape changes the morphology of the support. Nickel ferrite spinel from the reaction of Fe2O3 and NiO during co-firing produces spherical shaped macropores without a change in porosity. SOFCs fabricated by the addition of 0 wt%, 5 wt%, 10 wt%, and 20 wt% Fe2O3, exhibit maximum power densities of 2.24 W cm−2, 2.45 W cm−2, 2.38 W cm−2, and 2.09 W cm−2, respectively, at 800 °C with sufficient H2 fuel. With a lower H2 flow rate, SOFC fabricated without Fe2O3 shows fluctuating and lowered fuel cell performance. SOFC fabricated with 5 wt% Fe2O3 shows stable and improved performance. The dense percolation of spherical shaped macropores and a well-connected electrical conduction path, both of which are formed by adding Fe2O3, result in lowered charge and mass transfer polarization, which increase the fuel cell performance. However, as a result of the increased charge transfer polarization, the addition of 20 wt% Fe2O3 results in Fe diffusion into the anode functional layer and reduces the fuel cell performance. To obtain improved and stable fuel cell performance, the development of spherical shaped macropores is beneficial and the addition of other elements should be considered.